P0127 code meaning
Intake Air Temperature Too High
Powertrain system Generic code P01xx codes Check engine light
What P0127 means
P0127 is not a circuit fault but a functional check of the air path: the measured intake air temperature is too high for the operating state. The logic is documented for a Bosch EDC16 diesel (Saab 9-3): if the intake air exceeds 130 °C and does not fall below it within 45 s after the exhaust gas recirculation valve is closed, hot exhaust gas is evidently still entering or the sensor is wrong. The engine then disables EGR and runs in limp mode with reduced torque. GM has the code in its diesel software but disabled for US OBD II; Ford reports an overly hot intake air reading as P0111 instead. On other engines a hot reading can also come from warm under-hood air being drawn in.
P0127 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0127
- Check engine light on
- Loss of power, limp mode with torque limit
- EGR switched off
- Knock tendency and retarded ignition on gasoline engines
Common causes of P0127
- Most likelyEGR valve stuck open or not sealing (diesel)
- PossibleEGR cooler clogged or bypass flap stuck in bypass
- PossibleCharge air cooler dirty or airflow through it blocked
- PossibleSensor reading wrong, or hot engine-bay air drawn in (loose intake duct)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Intake air temperature sensorEGR valveEGR coolerCharge air cooler
What each part of P0127 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 27 | The exact fault in that area. |
What to do next
- Note P0127 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0127
What does P0127 mean?
P0127 means "Intake Air Temperature Too High". P0127 is not a circuit fault but a functional check of the air path: the measured intake air temperature is too high for the operating state. It is a generic code, so it means the same on every make.
Is it safe to drive with P0127?
Drive gently and only to a workshop. With P0127 the car can go into limp mode (reduced power) to protect itself.
Will P0127 fail an emissions test?
Yes, it can. P0127 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0127 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P0127 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.